多通道高速ADC电路PCB设计技术浅谈

Discussion on PCB Design of Multi-channel High Speed ADC

ADC是将模拟信号转换为数字信号的芯片,它在电路系统中的作用决定了它必然和其它大量数字电路一起使用,所以在其PCB设计中除了需要考虑一般PCB设计中要注意的问题之外,还要在多方面引起特别注意,尤其是在高速应用中[1]。本文就针对多通道高速ADC电路设计的特点,以E2V公司的EV10AQ190芯片为例,重点讨论了包含多通道高速ADC的硬件电路设计中印刷电路板布局时所必须引起注意的问题,包括数字地和模拟地,数字电源和模拟电源的处理,ADC输入信号的隔离问题,采样时钟的处理和输出信号的阻抗匹配等问题[2]。

Function of analog-to-digital converter （ADC） chip is to convert analog signal into digital signal, generally ADC chip will be used with other digital circuits because of its function in circuit system; therefore, when a PCB including ADC is designed, besides some common issues, other aspects should be considered especially in high speed application. Based on design features of multi-channel high speed ADC circuit, by taking E2V compa- ny＇s EV10AQ190 chips as an example, some issues which should be considered in arrangement of PCB including multi-channel high speed ADC are discussed, these issues include digital ground, analog ground, processing of digital and analog power supplies, isolation of ADC input signal, processing of sampling clock and impedance matching of output signal.